I've been playing an ARPG called Path of Exile lately, and the game seems to run way smooth in Fullscreen mode than it does in Windowed Fullscreen. The only problem I have is if a window pops up outside of the game, it'll minimize the game and pull me out of it. Since I'm playing a hardcore character, this is potentially deadly and a situation I'm looking to avoid. Is there any way possible to prevent another window from taking focus and minimizing another program like the game I'm trying to play?

I think you're looking at fixing the symptom not the problem. You need to get stuff to stop opening while your in a game, not to get the game to stop minimizing. If your computer is opening stuff in the background that will slow your game down weather your minimizing or not.

I think Aquinus hit it on the head. You need to stop the program that's popping up while you're playing. Example: Yahoo messenger running in the back ground will minimize your game when someone comes online and goes off line.. Or sends you a message..

I've actually never had the game minimize on me...yet. It's something I'm always worried about happening though. The one time it did minimize was because I plugged my phone in and the AutoPlay window popped up asking what I want to do about the Removable Disk that was just plugged in. So I'm mostly asking this as a preventative measure, I've invested about 3 weeks into this level 79 character, it would suck for it to die because the game got minimized for some unforeseen reason. So there's no way of forcing a window to always stay in focus or something along those lines?

Some other things I've tested though so not minimize the game, like a Steam message from a friend won't minimize. I'm not sure why some things do and some don't. But if there was a way to prevent it, I'd like to do it.